Hi, Tom. I appreciate your explanations and suggestions. Getting the accuracy I need is becoming critical and I'm becoming anxious. I have one of my IMUs in front of me now. Yes, it reads 0 when facing magnetic north. I think I recall seeing a video that explained the circular dependency you mention. That makes sense to me. But this is all still very fuzzy. I need some basic help with frames. Could you give me a simple first step or two? A launch file, for example, would be wonderful. Thank you! --- [Visit Topic](https://discourse.ros.org/t/tractobots-my-attempts-at-field-robots/1486/44) or reply to this email to respond. If you do not want to receive messages from ros-users please use the unsubscribe link below. If you use the one above, you will stop all of ros-users from receiving updates. ______________________________________________________________________________ ros-users mailing list ros-users@lists.ros.org http://lists.ros.org/mailman/listinfo/ros-users Unsubscribe: